1. Field of the Invention
The present invention relates to the field of wireless communications. More particularly, the present invention relates to mobile hosts communicating through a separate mobile router that provides seamless mobility services over one or more dissimilar networks.
2. Background Information
Within the last decade, wireless networks and the surrounding ecosystem of mobile computing products have been steadily gaining in market adoption. In many cases, enterprises have realized substantial productivity savings from the deployment of mobility products and services to their mobile workforce. In other cases, they have realized higher degrees of mobile worker flexibility, which have enabled them to offer differentiated products and services to their own markets. The increased flexibility and reduced cost that has been realized by the enterprise mobile workforce has contributed to continue to drive the market adoption rate of these mobility products and services.
Wireless carriers have made large investments building out new third generation public networks like GPRS, EDGE, 1×RTT, and 1×EvDO. Wireless LAN 802.11 networks have experienced widespread adoption and are now commonplace. Further, much of the legacy infrastructure, both private and public, remains in place with the owners of that infrastructure seeking to extend their return on the legacy investments.
There are existing patents like U.S. Pat. No. 6,826,405 to DOVIAK et al.; U.S. Pat. No. 6,198,920, to DOVIAK et al.; and U.S. Pat. No. 6,418,324, to DOVIAK et al., the contents of which are expressly incorporated by reference herein in their entireties, that teach improved simultaneous utilization of multiple networks. In these patents, users can seamlessly roam between dissimilar networks. As a mobile user goes out of range of a primary network, the user can continue to communicate over an alternate network.
Solutions created for seamless roaming between dissimilar networks have helped to promote the adoption of wireless networks. They allow mobile users to better take advantage of the varying strengths of the different networks and to minimize any limitations that they may exhibit. For example, 802.11 networks provide high bandwidth access over a narrow area and CDMA 1×RTT provides lower bandwidth over a wide area. Clients that are running mobility solutions can be configured to automatically use both networks. When in range of the 802.11 network (whether they are also in range of CDMA 1×RTT or not), they will take advantage of the increased throughput of that network. But when they roam out of the limited coverage area of 802.11 and remain in, or enter into, the coverage area of the CDMA 1×RTT network they will automatically take advantage of that network and its larger coverage area.
While this class of mobility solution substantially enhances the value proposition of enterprise workforce mobility, challenges remain that need to be solved in order to further drive enterprise adoption of workforce mobility products and services.
One such problem is the cost of participating in a wireless network. The cost of host mobility can come in many forms including the capital expenditure associated with the necessary communications devices, any recurring expense associated with network access through the communications device, and the overhead cost that each active communications device represents on the network infrastructure.
Another such problem is the administrative burden that mobility software represents. Traditionally, in order for a host to realize the benefits of seamless mobility, the typical solution requires that the mobile host install and run the mobility software stack locally.
One solution to the problems described involves the deployment of a mobile router that runs a seamless mobility solution and makes those services available to a mobile local area network. In this scenario, the mobile router aggregates access to the network infrastructure for all locally connected mobile hosts. This environment is often referred to as a mobile network. The use of a mobile router mitigates the cost of network access to a large extent by allowing multiple mobile hosts to share the upfront capital, recurring expense, and network overhead costs. However, the use of a mobile router still incurs much of the administrative burden described earlier.
Traditionally, when allowing mobile hosts to make use of the services of a mobile router, it has been required that either the mobile hosts continue to run a mobility software stack in tandem with the mobile router, or the mobile router be statically configured with the identities of the specific mobile hosts to which it will provide services.
In the first case, there is no change in administrative burden. In the second, there has been a reduction, although not an elimination, of administrative burden, but at the cost of a new restriction on mobile host mobility across mobile routers. When a mobile router is statically configured with the identities of the mobile hosts to which it will provide services, the mobile host is required to remain with the mobile router so long as it wishes to retain the same network identity.
In some cases, attempts have been made to provide seamless mobility services through a mobile router while allowing migration of mobile hosts between mobile routers. These attempts have all used Dynamic Host Configuration Protocol (DHCP) to implement the solution with the mobile router granting the DHCP lease from within the subnet range for which it provides mobility services. In this environment, although seamless mobility is maintained while associated with a single mobile router and a mobile host can now migrate between mobile routers, the local IP address of the mobile host must change when it migrates to a new mobile router. Therefore, seamless mobility is not maintained across a migratory event.
Another problem with the attempts that have been made to date is the homogenous nature of the local network of the mobile router. All solutions that have attempted to provide mobile routers offering mobility services to a local network have consisted of mobile routers that service either DHCP mobile hosts or statically addressed mobile hosts, but not both at the same time. However, mobile hosts have varying needs and some require static IP addressing while others require dynamic Internet Protocol (IP) addressing. Even in situations where no such requirement exists, it may be highly desirable to address the mobile hosts in different ways. For example, one host may be a mobile computer for which the administrator would prefer a DHCP address lease allocation. Another host may be a remote controlled camera that is servicing requests from client software running on other host computers. For this host, the administrator may prefer the IP address to be statically configured so that it is well known and easily reached by other host computers. For example, this situation could be present in a mobile vehicle area network in which different shift workers with their own mobile computers share the vehicle but the camera stays with the mobile router in the car. Another example may be a branch office network with workers moving between the branches but IP cameras remaining stationary in relation to the mobile router.
A further problem is access control. With the ability for mobile hosts to move freely between mobile routers and establish active communication sessions between varying mobile routers, questions regarding security and access control for the mobile host will need to be addressed by solution vendors.
Therefore, a need exists to allow for the automatic discovery of mobile hosts by a mobile router that is offering mobility services. Additionally, a need exists for mobile hosts to be able to dynamically migrate from one mobile router to another mobile router while maintaining uninterrupted seamless mobility and a constant local network identity. Further, a need exists to simultaneously support mobile hosts that are configured for static IP addressing as well as mobile hosts that are configured for dynamic IP addressing on the same mobile router. Finally, a need exists to provide migratory seamless mobility to a defined population of mobile hosts while restricting access for any mobile hosts that are not part of the defined population.